Microphone not working when making/receiving calls

On voice memos, the microphone works fine, but when making a call or receiving one, people can't hear me—even when the speaker is on. What could be the cause of this problem, and how does one repair it?

I don't really buy the noise cancelation mic issue here, I am a iphone tech at the ifix repair shop, and I have replaced the bottom mic(contained on the click and charge jack) and the top mic, and in most of the cases it fixes the problem for a short period of time before it just comes back and the mic no worky!! Sounds just like whats happening here, turn a screw here and there and the problem seems to be fixed, but then returns, all false positives. That audio IC has to be removed and re-balled and resoldered back onto the board for this problem to go away, so far I have only done 1 wich was successfull. keeping in mind I was re-balling by hand 0.2mm solder balls with a needle, hotair station and a magnifying glass. very intense work, takes about 2-3 hours.

So to what I know this is really the only fix, keeping in mind that sometimes when you "reset all settings" on the phone it can also make the problem go away for a little while, so it's no surprise that turning some screws here and there will also yield such an effect or even replacing the one of the mic's, but the real and only culprit here is the audio codec people!!!

took it to a repair guy and he said it's a software issue which makes sense considering voice memo etc... all work.

There seems to be a fix in iOS 5 that if you go to Setting --> General -->Accessibility --> Hearing and turn on Hearing Aid Mode the problem seems to disappear. At least it did for me and it saved me a ton of money in the process.

Ofc when you activate Hearing Aid Mode you disable the noise cancellation mic, so you can live with the problem but not face it. This way you don't have to understand where the problem resides (IC or standoff screw)!

Cardboard worked for me as well! I started off with upgrading (didn't help) and activating hearing-aid mode (neither did this), but I soon realized I had to open up the phone. At first, after applying the first bit of cardboard, nothing happened, so I tried to loosen the grounding screw near the camera, but still no solution. I had read that one might had to try different thicknesses of cardboard, so I did, and on third or fourth attempt I got it right! The piece of cardboard had to be so thick that it was almost tricky to slide on the back panel again. Thanks guys :-)

You are right. The IC may be faulty. However, it seems that is is not always the IC. In some cases indeed it is the IC, and when the IC is at fault then a normal call cannot take place even with a handsfree set (where the noise cancellation mic turns off). However in many cases the issue is caused (as already mentioned above) by a bad ground between a stand-off screw and the second noise cancellation mic. I recently faced two different issues. One with my phone where I tightened the screw and all came back to normal, and another phone where it was the IC.

On my iPhone, the mic could be re-enabled during a call by pinching the iPhone tightly at about the same point as the noise cancelling mic (next to the headphone jack). This would cause the mic to kick back in for a few seconds after you stopped pinching the device.

Tellingly, directly under the metal shield in that exact location are three press fit connectors for various IC's. I folded a small piece of paper and laid it across the backs of those three connectors. I then re-attached the shield and replaced the back cover. Mic problems seem to be gone for now (crossing fingers). I'm thinking that in some cases, the connector for the noise cancelling mic works a bit loose (or perhaps the sponge used to keep pressure on the connectors compresses somewhat). Time will tell, but right now, it seems to be working again.

The screw near the camera (big head one fixing the board to the metal body of the phone) seems in some cases to be guilty of this.

In total there are only 3 screws grounding the board to the 3 bands iPhone has. The one I'm talking is the one near the camera (back one) not the one down below the data connector nor the long small headed one near the headphone jack.

My fix was much more low tech...my iPhone apparently had acquired a righteous among of belly button lint in the screen for the mic. I used an old dry toothbrush and gently cleaned out the area and it looks and more importantly, works like new. Sometimes you gotta go low tech first...

Anyway, here the picture showing the location. Basically the standoff is a screw that holds the board to the frame and has a head with an opening to screw into, in this case the cover over all the ribbon connectors has a screw holding it down received by the standoff.

I also had this issue, and the microphone didn't worked, on receiving and placing calls. Buth using Viber/Voice Notes/Skype/etc worked flawlessly.

What i did,

I cleaned both microphones mesh holes, bottom and the top small hole besides headphone jack (this one was obstructed by grease or dirt, i used a brush and cleaned gentle inside it).

I already had changed the Dock/Microphone flex before this (which didn't fixed the issue).

I unscrew and screw again the top screws, leaving them not so tight, also cleaned the flex connector of the dock, with a soft brush and isopropylic alcohol. (i gave it a full brush all around the iPhone, removing dirt around it.)

worked for me. Requires a pretty good open heart surgery of your phone, if your comfortable with that. Use the dissecting guide found on this website to get to that chip. Once you get to it, you have to carefully pry off the EMI shield, one little by little, one side at time and go around a few times.

The tell all symptom for me was when using a hands free headphones, (the mic is in the button part of the headphones and not phone itself) and it still cut out during a call. Sometimes i hear static as well.

**THIS SOLUTION WORKED FOR ME, BUT MAY NOT WORK FOR OTHERS** I was having the same issue and couldn't get it to work AT ALL. So for whatever reason, I decided to use my digital caliper to measure the screw. For anyone confused, the screw that is spoken of, is the screw that is on the FAR LEFT of the Wi-Fi EMI shield right below the camera. The screw measured at 2.5mm instead of the factory SUPPOSED measurement of 2.3mm. I switched out the screw with one that DID measure at 2.3mm and it completely and permanently fixed the problem. I spoke with an Apple representative two months later when I was sure that the problem was fixed, and they told me, "we're well aware of the problem and anyone with an iPhone still under warranty, may turn their iPhone 4 in to be repaired or replaced." I know it's extremely stupid that this was a "valid" response, but I hope this helps!

I had dropped my phone, and I was in the middle of a phone conversation … I could still talk to the person, and I could hear her … but after our conversation was done, I tried to call my daughter. She could not hear me, and I could not hear her. Texting and everything else worked fine, but even the noise as you type texts into the phone was muffled. I slapped the phone a couple of times on my hand, and the texting noise came back, but still the audio on the phone would not work.

After discovering my problem was also somebody else's problem online, they fixed it this way:

go to Settings>General>Reset>Reset Network Settings.

Apparently this resets back to the original network settings, but nothing changed on my phone -- except I HAD MY AUDIO BACK!!! Didn't have to go to the Apple store, didn't have to break into my phone to attempt to fix it manually, just had to push a few buttons. Phew!!! No need for a new iPhone!

I tried to clean the upper mic as shown in one youtube video and it did not work for me. Then I just went ahead and bought a tiny size 3.5mm Microphone Speaker that is usually used to enhance the voice quality of video recording. This works like a charm and it was just $10 buck at amazon.

I tried all the above and nothing worked. I even sent it to a repair firm who changed the mic and the power button bizzarly - they then said the phone was unrepairable! I rang a guy I found on google - Mike on 01924 262112 and he sorted it within an hour. I cant remember what he said cured it but it wasn't software. I think his company is called iphone repairs direct - really helpful and I can ring my friends again - happy girl :)

Do this, open the back of the phone. Make call to another phone and put that speaker on. While calling , press down on the back of the circuit board where the sim card lay, right where the clear plastic tab (to remove the battery is) and press down on that. You'll notice that the mic then will work. So put the cardboard precisely there, adjust thickness to get it to work. Good luck!

I see alot of these. I fixed two today with this problem. Both were fixed by replacing the dock connector mic assembly. When the mic works on apps and voice memos it is using the top mic. The bottom mic works on calls.

I agree totally with Noel Br - there are loads of 'I've fixed it' and 'totally worked for me' shouts from folks who've had a quick results from the bit of paper od cardboard or paper 'fix', but isn't a fix at all, just a temporary solution to what is essentially a manufacturing defect. The audio IC, as Noel says, is a BGA device, and not really repairable by man-in-the-street, as it requires some specialised kit to achieve. I'm also well hacked off at Apple for their failure to warranty against this kind of issue - it's a result of poor quality control at manufacture. sorry guys, but it has to be said!

@Craig, are you sure of that because when you open Voice Memos if you blow gently into the bottom mic it registered volume but the top mic doesn't register at all. I've tested that on a number of phones including the one I think is faulty.

I solved mine just today. I had to open up the phone to get to the audio codec chip. Used a small paper tape to glue it down firmly. Now it works perfectly. Follow the link provided above http://www.beijingiphonerepair.com/fix/d... For a clearer understanding

My problem was solved by just resetting the iPhone: push on/off button & home button simultaneously, and microphone was working again. It was as simple as that. - Special thanx to the lady of the Apple store (the guys there didn't know that aparently)..

a great fix that i found out worked way better than paper or cardboard (on the back near the mic cancellation) is blu tac! just put a small amount and it will mould around the area that need to have pressure on it! good luck guys!

Paper didn't work for me:( I'm wondering if they fix it in 6.1 as it is strange it works with other apps but not with gsm calls. And it is too bad that there is no workaround with headset or bluetooth..

In my experience it is due to the cable the connect the dock connector to the logic board. So I have seen a method where people put a piece of cardboard inside on top of the flex cable, but also replacing the dock connector for about $10-15 has always worked for me! You can find a tutorial on how to do it on this website.

Okay I did some research and I figure it all out no it's not a hardware or issue or a software issue it's actually kind of simple

There's a new mic and that would be at the tip next to the headphone jack the little hole if there's something covering that hole no sound goes through I have slick wraps so it was being covered I took it off and did a video record test and the audio went through try it for your self when recording a video just tape that hole or put ur figure just to test it out and you will see. Hope this was some useful information.

Update

BUT I SAY:

THE PROBLEM IS THE BASIC (DOWN NEAR TO THE CHARGING JACK) MICROPHONE, OPEN THE BACK COVER OF THE IPHONE AND TAKE OUT THE MICROPHONE CAREFULLY, AND CLEAN THE MICROPHONE COVER FROM THE OUTSIDE AND INSIDE AND CAREFULLY CLEAN UP THE SMALL HOLE OF THE MICROPHONE ITSELF. THIS IS THE ONLY SOLUTION. USE A WOODEN TOOTH CLEANER STICK.

I've been struggeling with exact issue as described above (mic not working during calls, rest is fine).

Summary:

Fixed it by putting on all spund and vibration signals in the menu by going to:

Settings > sounds > vibrate both on, sound all the way up, change with buttons on.

Received a call and then it worked.

It is now fixed, I'm not sure why and if this is of any help, but you can always try.

What I have tried:

- reset netwerk setting (thought that was the issue)

- hard reboot

- cleaning both mics (externally)

- in menu

- toggling hearing aid mode in menu ("gehooraparaatmodus")

- etc. Etc.

Noting worked. I also pressed outside, it's back (mostly beating out of frustration), plugging in and out a jack.

Them... I stopped giving a $@$*...

But the only thing that I have changed before it started working again is the following:

I had my phone in silent mode (only vibrate), I received some whatsapp calls since that worked fine, however, missed al the calls because of silent mode. I then put on all sounds and vibrations in full. I received a regular phonecall so I say: listen man you know you can't hear me so why call (was my brother with whom I was testing lot of things). And he responed: What are you talking about, I can hear you just fine.

Did some test calls, worked fine. Put phone back on silent mode, works fine. So it is fixed (for now).

Hope this helps, it is an easy fix if it helps you so you can try real fast. Let me know.

Note:

Could be related to the physical sound on of button (is not working too good on my phone).